The catalytic dehydrogenative polymerization of tetrahydroquinoline and certain organo substituted tetrahydroquinoline compounds is disclosed in U.S. Pat. 4,727,135. The polymers produced in the disclosed process contain repeating quinoline moieties. For example, the transition metal sulfide (TMS) catalyzed dehydrogenative polymerization of 1,2,3,4-tetrahydroquinoline (1) produces polyquinoline (2) as shown in Equation 1 below. ##STR4## Similarly, the dehydrogenative polymerization of 3-mono organo substituted tetrahydroquinoline (3) produces a substituted polyquinoline polymer having a 3-organo substituted quinoline moiety (4). This is shown in Equation 2 below, where R represents the organo substituent. ##STR5##
These polymers constitute an important class of electrically conducting organic materials that have use in batteries, photoconductive cells and the like.
In copending application Ser. No. 155,225, filed Feb. 12, 1988, quaternary ammonium salts of polyquinoline oligomers are disclosed and shown to have use as metal corrosion inhibitors.
In contrast to the above mentioned references, U.S. Pat. No. 4,275,191 discloses that quinoline will not undergo polymerization, except at elevated pressures and temperatures of between 250.degree. C. and 400.degree. C. and in the presence of catalytic amounts of certain alkyl halides. The product of the polymerization, however, does not have repeating quinoline moieties but, instead, is represented by formulas 5 and 6 shown below. ##STR6##